A199988 Numbers whose product of digits is 6.

6, 16, 23, 32, 61, 116, 123, 132, 161, 213, 231, 312, 321, 611, 1116, 1123, 1132, 1161, 1213, 1231, 1312, 1321, 1611, 2113, 2131, 2311, 3112, 3121, 3211, 6111, 11116, 11123, 11132, 11161, 11213, 11231, 11312, 11321, 11611, 12113, 12131, 12311, 13112, 13121

Offset: 1

Author

Jaroslav Krizek, Nov 13 2011

Keywords

• nonn
• look
• base

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A034053.

Cf. A007954.

Programs

Maple

f:= proc(d) local b,i,t;
   b:= (10^d-1)/9;
   op(sort([seq(b+5*10^i,i=0..d-1),seq(b+10^t[1]+2*10^t[2],t = combinat:-permute([$0..d-1],2))]))
end proc:
seq(f(i),i=1..5); # Robert Israel, Jan 13 2021

Mathematica

Select[Range[20000], Times @@ IntegerDigits[#] == 6 &] (* T. D. Noe, Nov 16 2011 *)

Python

from sympy import prod
from sympy.utilities.iterables import multiset_permutations
def agen(maxdigits):
    for digs in range(1, maxdigits+1):
        for mp in multiset_permutations("1"*(digs-1) + "236", digs):
            if prod(map(int, mp)) == 6: yield int("".join(mp))
print(list(agen(5))) # Michael S. Branicky, Jun 16 2021